DE1930091A1 - Color television cathode ray tube arrangement - Google Patents

Description

Color television cathode ray tube assembly This invention relates to a color television cathode ray tube assembly of the pinhole or shadow mask type with magnetic devices to correct the beam positions.

The typical ones currently used for color television home receivers Cathode ray tubes have a faceplate on their inside or back with a layer of fluorescent dots each arranged in groups of three (triplets) is provided, the fluorescent dots of each triplet when excited by a Electron beam each emitting red, green and blue light behind the colored phosphor layer (which are deposited with an aluminum layer) there is a hole or shadow mask, i.e. a perforated metal frame with its holes so arranged are that there is a hole behind the center point of each color-fluorescent point group lies. In the neck of the tube are three Metal electron beam systems symmetrical arranged distributed around the central axis of the tube neck. The individual electron beam systems are each aligned so that the electron beam generated by them passes through the openings of the shadow or perforated mask pass through at such an angle, that it only hits fluorescent points of one color at a time.

The individual electron beam systems can thereby through the color of the fluorescent points on which the beam generated by the system hits, emitted light, a typical tube therefore has a red one Electron beam system, a green electron beam system and a blue electron beam system on.

The individual electron beam systems each point in the direction Seen from the back of the tube towards the front to the front panel, the following parts on: a heating coil, one heated by the heating coil to emit electrons Cathode, a control electrode (commonly referred to as G1) that determines the number of controls flying electrons from the cathode towards the front of the tube, a second or accelerating electrode (G2 which holds the emitted electrons attracts, as well as third and fourth electrodes (G 3 and G4) for further acceleration and focusing or collimation of the electrons so that a narrow bundled Electron beam is directed onto the faceplate of the tube. The inside of the The front panel and the side walls of the tubes are conductive and form a second The anode was the fifth electrode.

In a typical tube with a diagonal screen size in the range of 17 inches up to 23 inches is the control electrode G1 usually to a negative Voltage about 50 V below the cathode voltage, the first acceleration electrode G2 usually has several hundred volts positive to the cathode, and the second anode about 25,000 V positively biased towards the cathode. The first of the two focusing electrodes G3 is usually biased positive to cathode at about 4,000 volts, and the second Focusing electrode G4 becomes at a final acceleration voltage equal to the chimp potential (25 kV). The focusing and accelerating electrodes are spaced apart are arranged from each other and are kept at different tensions, in such a way that that electrostatic fields exist between them, which are called electronic lenses act to collimate the electron beam.

There are various magnetic devices around the tube neck intended to influence the position of the individual electron beams. From the front At the end of the tube neck, seen from the rear, there is initially a deflection yoke in the front Part of the tube neck to the funnel part of the tube then on the tube neck intended; the magnetic fields generated by this yoke cause the electron beam for executing the scanning movement across the tube screen in a row of adjacent ones horizontal line paths. Behind the deflection yoke is this surrounding area on the tube neck proposed a convergence yoke order; this device has permanent and Electromagnets, which the static and dynamic respective radial position influence the individual electron beams in such a way that all three beams converge, i.e. when scanning over the front plate of the tube essentially on the hit the same place.

The convergence device are six radial inside the tube neck Pole cloths (two for each electron beam) assigned to that of the convergence device concentrate the generated magnetic field in strange directions, so, that the electron beams in their respective positions in the desired manner in radial Direction can be shifted. Behind the convergence device is on the tube neck a "blue lateral" permanent magnet device is provided, by means of which the Lateral lateral position primarily of that which excites the blue fluorescent dots Beam is controllable, as a further measure to achieve a suitable convergence.

So that each electron beam only has its fluorescent points When a special color is excited, it is necessary that each beam is in each case the shadow mask reached at the right angle. It is theoretically possible to do this by arrangement of the three electron beam systems in certain precise positions in the tube neck to reach. However, since it is not possible to use these exact adjustment positions in To adhere to mass production, there is a color purity "magnet assembly Application, which the respective position of the electron beams in the required Corrected way so that they reach the shadow mask at the correct angle. The color purity magnet device is usually on the tube neck in the area the gap between the G2 and G3 electrodes behind the blue lateral magnet device arranged.

There is a problem with such a cathode ray tube assembly in that the accelerating and focusing electrodes of the electron beam systems three different voltages must be supplied. As mentioned at the beginning, must the acceleration electrode (G2) has an initial acceleration voltage of approximately 400 V are supplied to the first focusing electrode (03> a focusing voltage of about 4000 V, and the second focusing electrode (G4) a final acceleration voltage (25 kV). The supply of the first and the third pre-tensioning mentioned above offers no difficulties because the 400 V accelerating voltage can be taken from the B + voltage source of the receiver and the 25 kV final acceleration voltage is already present on the second anode of the tube.

The requirement for a special 4 kV focus voltage forms however, a problem as there is no such voltage elsewhere in the tube or the circuit chassis is available. This voltage must therefore be generated specially will. This usually requires an additional winding on the horizontal output transformer of the associated receiver provided, with appropriate circuit parts, such as Equal rights, filters and limiters. For those skilled in the art it is readily apparent that it from the point of view of cost, operational safety, weight and simpler service would be extremely desirable if this additional voltage source could be made dispensable. "Single" type electron beam systems, which do not require such an additional voltage source, have not been used until now, as they lead to electron beams with an excessively large light spot on the front panel of the pipes.

The present invention has for its object to provide a color television cathode ray tube assembly, for which no such special focusing voltage source is required, without any deterioration, in particular an increase in the Electron beam spot on the front plate of the tube must be accepted would have to; due to the omission of the separate focusing voltage source should simultaneously increased operational reliability, lighter weight, lower cost and easier service can be achieved.

To this end, see the color television cathode ray tube assembly according to the invention a cathode ray tube with three electron beam systems application, each having a focusing lens of single Trp.

Such a single focusing lens has a first and a third focusing electrode, which is at the potential of the second anode of the cathode ray tube are held, as well as an intermediate second, shorter electrode on which is held essentially at the cathode potential. With the arrangement according to of the invention is the color purity magnet device on the tube before the second focusing electrode and arranged behind the convergence yoke device, and the blue lateral magnet device is in front of and behind the convergence yoke Deflection yoke attached.

In the following embodiments of the invention are based on the. Drawing described; 1 shows a schematic view of a color television cathode ray tube arrangement according to the r erection; The Pigg. 2a and 2b for use in the arrangement according to FIG Fig. 1 certain Reinhelts- and ulateral magnets, as well as the effect of the fields these magnets on the position of the electron beams.

Fig. 1 shows the color television cathode ray tube arrangement according to the invention in a partially sectioned, partially schematic view, with parts broken away.

The tube has an evacuated glass bulb with a neck part 10, a funnel 12 (which is largely omitted in the drawing to save space is), as well as a front plate 14. On the inside of the faceplate 14 is a layer 16 of color phosphor dots applied, on the back of a Aluminum layer can be provided.

Behind the phosphor layer 16 is a perforated metal loob mask 18 arranged. The inside of the funnel-shaped part 12 and the front part of the neck part 10 are with a. conductive coating 20 provided £ for example the Graphite preparation marketed under the name "Aquadag". The "Aquadag" cover 20 is in contact with the aluminum-coated phosphor layer 16 such that that the entire inner surface of the faceplate and the funnel-shaped part 12 of the tube represents a second anode.

A 25 kV voltage source 22 is connected to the Aquadag coating, which holds the second anode at this potential.

Three electron beam systems are housed in the tube neck 10, namely in a symmetrical arrangement at the corners of an imaginary equiangular Triangle whose plane is perpendicular to the tube axis. The tube is shown in the drawing 1 at such an angle that two of these electron beam systems, namely, systems 26 and 28, are equidistant from the viewer; not that one shown) third electron beam system is therefore between the two shown Systems and behind one of them. The upper electron beam system 26 is in Section, the lower system 28 shown in side view.

Since the individual elements of the electron beam system are of the same kind are, they are denoted by the same reference numerals, the reference numerals for the lower system 28 are provided with a line.

Each of the jet systems has a heating coil 30 for heating a cylindrical cathode 32 surrounding the winding; the cathode 32 is each closed at one end by a wall, the outer surface of which with is provided with an electron-emitting coating.

The cathode 32 is cylindrical in its front part Control electrode G1 surrounded by a wall with one end face a central opening for the passage of electrons is closed. In further A cylindrical acceleration electrode G2 is provided spaced from the cathode; This is on its rear face with a similar wall with opening for Provided passage of the electrons in such a way that the partially closed end face the electrode G2 faces the partially closed end face of the electrode G1.

The front end face of the electrode G2, as are the end faces by the way most of the other electrodes, too, can be seen in the drawing Way flanged outwards and backwards, so that they are the face of each adjacent electrode presents a rounded, curved surface to a Avoid arcing.

The next electrode G3 is a focusing and accelerating electrode, which consists of a relatively narrow, rear cylinder part with a relatively wide front cylinder part in the manner shown by an im substantially radially extending wall is connected. The rear face of the narrow part is located inside the front end of the electrode G2. The next one Electrode G4 is a cylindrical focusing electrode that is open at both ends and has a smaller axial lung than electrode G3. The final focus electrode G5 has a cylindrical rear part, the rear end of which widens in a funnel shape and is bent away from the electrode G4. The front parts of all three G5 electrodes are connected to one another to form a conventional, uniform structure, the radial pole pieces (not shown) and sectors (also not shown) for mutual isolation of the individual pole piece sets. To each of the G5 electrodes, a connecting part 34 is provided, the Elektrison G5 electrode structure with the Aquadag cover 20 / connects.

On the rear face of the tube neck connection or. Socket pins provided, by means of which the necessary bias voltages and signal voltages are fed to the various n electrodes of the electron beam systems by means of rigid inner connecting lines (not shown in the drawing).

The heating windings 30 are connected to the usual heating voltages, for example 6.3 V AC voltage. The cathodes 32 are biased to a reference potential, the reference potential used in the circuit of the color television receiver can be different; in the drawing, however, the cathode reference potential is through indicated by a mass symbol.

The cathode 32 can also have a signal voltage, for example one Chrominance or chrominance information, 0 In this case it is between the cathode and the circuit point at reference potential a (not shown) suitable load impedance provided. The control electrodes Gl are negative Potential of about -50 V biased; them can be a brightness or luminance signal be fed. The acceleration electrodes G2 are biased to a positive voltage, which can be around +400 V in a bypic 23-inch tube. The first focusing electrodes G3 are connected between G3 and G5 by means of the connecting lines 35 shown the potential of the G5 electrodes biased. As will be explained below, these electrodes in a typical tube are at a potential greater than held about 100,000 volts, typically 25,000 volts. The second or intermediate focus electrodes O4 are essentially biased to cathode potential. Given the great Potential difference between the electrodes G4 and the electrodes surrounding them G3 and G4 conclude the statement that the electrodes G4 "essentially at cathode potential" are biased, a bias of the electrodes G4 to a few 100 volts a potential different from the cathode voltage, for example on the voltage of the G2 electrodes (+400 V). The third focusing electrodes G5 are by means of of the connecting parts 34 are biased to the voltage of the second anode (+25 kV).

The focus electrodes G3, O4 and G5 form a three-electrode electron lens from the so-called "single Trp", since their optical counterpart is on both sides of Media with the same refractive index is surrounded by a single-line lens, around the front part the tube neck around a her conventional deflection yoke 24 is arranged, the magnetic fields the electron beams from the tube neck to the front panel in Dependence of horizon and vertical deflection signals on a scanning movement Ub ¢ r cause the front panel.

Also on the tube neck, behind the deflection yoke 24 and in alignment with the front portion of electrode G5, did a convergence yoke arrangement 36 is provided, which consists of three permanent magnets and three associated electromagnets consists of which pole pieces (like the one shown at 38) for coupling magnet energy to the radial pole pieces (not shown) inside the front part of the electrodes 05 own.

In front of the convergence yoke 36 and adjacent to it is on the tube neck a blue lateral magnet arrangement 40 is provided.

In the drawing, the blue lateral arrangement 40 is more symmetrical Position shown with respect to the main axis of the tube; in reality is; the lateral arrangement arranged a @ ymmetrically for a reason to be described below, in such a way that that its center lies slightly below the main axis of the tube. Also on the tube neck behind the convergence assembly 36 and in front of the space between A chromaticity magnet assembly 42 is located across electrodes G4 and G5.

The deflection yoke, the convergence yoke arrangement, the blue lateral magnet arrangement and the purity magnet assembly are all conventional; for the better Understanding of the invention is however in Figs. 2a and 2b each one of the purity magnets and the blue lateral magnets.

The purity magnet arrangement consists of two ring magnets of the in 2a, which can be seen at 42 in FIG. 1, placed against one another are. Each of these magnets has the shape of a flat ring and is so magnetized that it is at opposite ends of its perimeter has north and south poles as shown. With this arrangement, the Inside the tube neck a magnetic field is generated, indicated by the dashed lines is indicated. In a known way, the strength and direction of this field can be determined by Turning one or both magnets can be optionally adjusted. The generally lateral ones Are shifts of the beam positions through a field with vertical orientation illustrated by the dashed and solid circles representing the Reproduce beam positions without or with the use of a purity magnetic field.

The blue lateral magnet arrangement consists of two flat toroidal shapes Parts of the kind shown in Fig. 2b, which are polarized so that they are on their periphery Have three north and three south poles as shown in the drawing. Which are located inside the tube neck with an asymmetrical arrangement of the blue lateral magnet system with respect to the electron beams resulting field distribution is also indicated by a dashed line Lines indicated. The direction and strength of these magnetic fields can be varied as desired Turning one or both of the blue lateral magnets can be adjusted. The one from this one Magnetic fields are such that they change the position of the topmost beam (which in practical use is the blue ray) in a lateral direction and the positions of the other two (green and red) rays to a lesser extent adjusted in the opposite direction.

Mode of operation of the arrangement described In operation, the each cathode 32 emitted electrons in a conventional manner controlled by the electrodes Gl to G5, accelerated and collimated that three narrowly bundled electron beams on the front panel the tube hit. The dynamic magnetic field generated by the deflection yoke 24 causes the electron beams in a conventional manner to perform a scanning movement via the front panel of the tube. The permanent magnets of the convergence magnet assembly 36 are set, and the electromagnets of the convergence magnetanor signals supplied that the radial position of the rays are corrected so that the rays converge as they scan across the tube faceplate. The blue lateral magnet arrangement 40 gives an additional static lateral convergence correction by adding dje lateral position of the blue beam in the desired direction and the position of the red and shifts the green ray to a lesser extent in the opposite direction, such that the blue ray converges with the red and green rays. the The position of all three emitters is, overall in a lateral direction, through the Field of the purity magnet assembly 42 shifted so that all of the rays die Hit the shadow mask 18 at the correct angle so that each beam only has fluorescent points a single color excited.

The single lens consisting of electrodes G), G4 and G5 is generated two strong electrostatic fields, one between electrodes G3 and G4 and another between electrodes G4 and 05. Of these, the first is Field divergent and the second convergent. Overall, the two lenses do one Collimation and focusing of the electron beams in such a way that they do so when they strike have as small a light spot as possible on the tube front plate Single lens makes a special focusing voltage source of the order of magnitude of 4 kV dispensable; however, it was found that electron beams, if they do not penetrate the electrodes of the individual lens along their central axis, a experience a very large expansion, and therefore a large one on the front plate of the tube Result in a light spot, which leads to poor focusing (washed-out, blurred Images) leads. For this reason, a single lens has hitherto been used not thought possible in a shadow mask tube. According to the present invention the beams do not emerge from the respective central axes of the electron beam generating systems concerned distracted there. the purity magnet assembly 42 and the blue lateral magnet assembly 40, which, as illustrated in FIG. 2, cause such a deflection of the beams when placed above or behind the lenses, are placed in front of the lenses sind4 In this way, according to the present invention, a single lens in one: color television cathode ray tube usable without any magnification of the electron beam spot. The respective position shown of the purity magnet and the blue lateral magnet is in fact proportionate critically, as mentioned, it is not relevant to either the purity magnet arrangement or the blue lateral magnet arrangement above or behind the individual lenses (dho above or behind the space between G4 and G5) without a serious Deterioration of the spot size occurs, too, is it not accessible to that To arrange purity and the blue lateral magnet arrangement near or in front of the deflection yoke, since a much stronger magnet would be required at such a point, its Field cause an unacceptably large magnetic distortion of the electron beams would. According to the invention, the purity magnet is in front of the rear end of the G5 electrode, and preferably behind the convergence yoke and in the region of the rear end of the G5 electrode, arranged, The blue lateral magnet arrangement is between the convergence yoke and the deflection yoke, preferably adjacent to the convergence yoke, arranged.

In the known color television cathode ray tube assemblies Electron @ beam systems used by the non-single tup, with the purity magnet arrangement located near the rear end of the tube neck, i.e. in the region of G2 was. In the tube arrangement according to the invention, the purity magnet arrangement is placed in the front part of the tube neck, where theoretically a larger magnetic flux is necessary for an equivalent correction of the electron beam. However has surprisingly been found that when attached in the according to the invention no stronger purity magnets are required because of the leakage flux behind the purity magnet arrangement, the electron beams in the known arrangements no longer penetrated, now penetrated by the electron beams and therefore with the Attachment according to the invention is usefully utilized. This is practical for the purity magnet assembly when attached according to the invention required magnetic flux because of the mentioned utilization of the leakage flux about 25% lower than with known ones Arrangements.

Experimentally it was found that a tube arrangement with typical convergence and purity settings for an electron beam system of the single lens type with the arrangement of the purity magnet arrangement and the blue lateral magnet arrangement in the positions shown in FIG. 1, a 35% reduction in the electron beam leak spot size compared to the conventional arrangement of the magnet assemblies, Since also the purity magnet arrangement, the convergence yoke and the blue lateral magnet arrangement are all arranged relatively close together, these three parts can in a simple way to a unified Formations summarized thereby reducing assembly and service costs.

The invention was based on a preferred exemplary embodiment described, but of course in various ways in detail can be modified without thereby departing from the scope of the invention.

- patent claims -

Claims (6)

Claims 1. color television cathode ray tube assembly, with a cathode ray tube which has one neck and one at its wide end with; e.J.ner a. Le @ chts @ off arrangement supporting front plate closed funnel part aufweisr, with several electron beam systems arranged in the neck @@ for Generation of several electron beams directed onto the front panel, each Electron beam system, in the longitudinal direction of the tube from back to front in the direction to the front face consecutive, a cathode, a besügli @ h of the cathode a negative potential biased cylindrical control electrode and several has cylindrical focusing electrodes arranged at a distance from one another, at least one of which to a potential at least 10,000 volts higher than the cathode is biased, with one arranged on the front part of the tube neck Deflection yoke, which the electron beam @ z @ the scanning movement over the front panel caused by the tube, with one arranged on the tube neck behind the deflection yoke Convergence device for influencing the radial positions of the electron beams, as well as with a color purity correction device arranged on the tube neck to change the radial position of the rays, thereby g e k e n n z e c; r. a C t that the electron transfer systems have three focusing electrodes (G3, G4, G5), of which the first (G3) and grits (G5) are essentially are biased to the potential of the front plate (14) and the intermediate second focusing electrode (G4) essentially at the potential of the cathode (30, 32) is biased, and @ that the color purity correction device (42) on the tube neck (10) in the area behind the convergence device (36) and in front of the space between the second (G4) and third (G5) focusing electrodes is arranged. 2. Cathode ray tube assembly according to claim 1. characterized g e k e It is noted that the color purity correction device (42) has at least one the tube neck (10) enclosing ring magnet (Fig. 2a), which on his Perimeter has a north pole (N, Fig. 2a) and a south pole (S, Fig. 2a). 3. Cathode ray tube assembly according to claim 1 or 2, with a further arranged on the tube neck magnetic correction device by means of which the lateral position of at least one of the electron beams with respect to the remaining electron beams is adjustable (blue lateral magnetic device), thereby It is noted that the additional lateral magnet correction device (40) on the tube neck (10) in the area behind the, deflection yoke (24) and in front of the Convergence device (36) is arranged. 4. Cathode ray tube assembly according to one or more of the preceding Claims that the electron beam systems (26 to 2B) each between the control electrode (G1) and the first focusing electrode (G3) additionally has a ring-shaped or cylindrical acceleration electrode (G2), which on a between the potential of the cathode (32) and the potential of the front panel (4o) lying potential is biased. 5. Cathode ray tube assembly according to one or more of the preceding Expectations. as a result, the second or middle focusing electrode (G4) of the electron beam systems, respectively a lesser axial Longitudinal stretch in the direction of the longitudinal axis of the tube than the first (G3) and third (G5) has focusing electrode. 6. Cathode ray tube arrangement according to one or more of the preceding Claims, in training as a shadow mask tube for a three-beam @ r @@ component color television system, thereby g e k e n z @ @ @ h n e t that the front plate (14) of the tube on its Inside or back with a fluorescent layer (G6) made of fluorescent point triplets is covered in three different colors, behind which a perforated metallic shadow mask (18) is provided, and that in the tube neck (10) around the tube's longitudinal axis her @@@ distributed three electron beam systems (26 to 26) @ou can see which ones at a distance from each other at the @@ k @ points of an imaginary equiangular triangle angeo @@@@ e @ whose plane is perpendicular to the tube axis L. e e r e i t e